It is well known in the art to use dielectric stiffeners in the manufacturing of antennas, especially between reflector shells of dual-gridded reflectors (DGRs), to minimize the RF (radio frequency) impact of such stiffeners on the overall antenna RF performance. Although dielectric materials such as Kevlar™, glass fibers and the like are used, the stiffeners are not ideal RF transparent structural posts and result in antenna field disturbance with typical increased sidelobe degradation of the signal.
Photonic bandgaps (PBGs) have been recently developed and used in microwave based applications such as in transmission lines with enclosed or channeled fields, including closed and open wave guides and the like, in which all the RF signal gets transmitted through. PBG structures include periodically disposed electrically reflective elements and exhibit RF properties that prevent propagation of electromagnetic waves in a specific direction at pre-determined frequency bands.
Known PBG technology is not applicable to open field antennas because of the relatively large signal cross-sectional path they have at any location between the feed and the reflector of the antennas, as opposed to transmission lines.
Accordingly, there is a need for an electromagnetic bandgap antenna structural element that improves the overall antenna performance.